<?php
defined('BASE') or exit('Access Denied!');

/**
 * Obullo Framework (c) 2009.
 *
 * PHP5 MVC Based Minimalist Software.
 * 
 * @package         obullo       
 * @author          obullo.com
 * @copyright       Ersin Guvenc (c) 2009.
 * @filesource
 * @license
 */

Class TypoException extends CommonException {} 
 
// ------------------------------------------------------------------------

/**
 * Typography Class
 *
 *
 * @access      private
 * @category    Helpers
 * @author      Obullo
 * @link        
 */
 
Class typography_CORE implements PHP5_Library {

    // Block level elements that should not be wrapped inside <p> tags
    public $block_elements = 'address|blockquote|div|dl|fieldset|form|h\d|hr|noscript|object|ol|p|pre|script|table|ul';
    
    // Elements that should not have <p> and <br /> tags within them.
    public $skip_elements    = 'p|pre|ol|ul|dl|object|table|h\d';
    
    // Tags we want the parser to completely ignore when splitting the string.
    public $inline_elements = 'a|abbr|acronym|b|bdo|big|br|button|cite|code|del|dfn|em|i|img|ins|input|label|map|kbd|q|samp|select|small|span|strong|sub|sup|textarea|tt|var';
    
    // array of block level elements that require inner content to be within another block level element
    public $inner_block_required = array('blockquote');
    
    // the last block element parsed
    public $last_block_element = '';
    
    // whether or not to protect quotes within { curly braces }
    public $protect_braced_quotes = FALSE;
    
    private static $instance;
    
    public static function instance()
    {
       if(! (self::$instance instanceof self))
       {
            self::$instance = new self();
       } 
       
       return self::$instance;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Nothing to do here...
     *
     */
    public function init() 
    {
        log_message('debug', "Typography Class Initialized");
        
        return self::instance();
    }

    /**
     * Auto Typography
     *
     * This function converts text, making it typographically correct:
     *     - Converts double spaces into paragraphs.
     *     - Converts single line breaks into <br /> tags
     *     - Converts single and double quotes into correctly facing curly quote entities.
     *     - Converts three dots into ellipsis.
     *     - Converts double dashes into em-dashes.
     *  - Converts two spaces into entities
     *
     * @access   public
     * @param    string
     * @param    bool    whether to reduce more then two consecutive newlines to two
     * @return   string
     */
    public function auto_typography($str, $reduce_linebreaks = FALSE)
    {
        if ($str == '')
        {
            return '';
        }

        // Standardize Newlines to make matching easier
        if (strpos($str, "\r") !== FALSE)
        {
            $str = str_replace(array("\r\n", "\r"), "\n", $str);            
        }
            
        // Reduce line breaks.  If there are more than two consecutive linebreaks
        // we'll compress them down to a maximum of two since there's no benefit to more.
        if ($reduce_linebreaks === TRUE)
        {
            $str = preg_replace("/\n\n+/", "\n\n", $str);
        }   

        // HTML comment tags don't conform to patterns of normal tags, so pull them out separately, only if needed
        $html_comments = array();
        if (strpos($str, '<!--') !== FALSE)
        {
            if (preg_match_all("#(<!\-\-.*?\-\->)#s", $str, $matches))
            {
                for ($i = 0, $total = count($matches[0]); $i < $total; $i++)
                {
                    $html_comments[] = $matches[0][$i];
                    $str = str_replace($matches[0][$i], '{@HC'.$i.'}', $str);
                }
            }
        }
        
        // match and yank <pre> tags if they exist.  It's cheaper to do this separately since most content will
        // not contain <pre> tags, and it keeps the PCRE patterns below simpler and faster
        if (strpos($str, '<pre') !== FALSE)
        {
            $str = preg_replace_callback("#<pre.*?>.*?</pre>#si", array($this, '_protect_characters'), $str);
        }
        
        // Convert quotes within tags to temporary markers.
        $str = preg_replace_callback("#<.+?>#si", array($this, '_protect_characters'), $str);

        // Do the same with braces if necessary
        if ($this->protect_braced_quotes === TRUE)
        {
            $str = preg_replace_callback("#\{.+?\}#si", array($this, '_protect_characters'), $str);        
        }
                
        // Convert "ignore" tags to temporary marker.  The parser splits out the string at every tag 
        // it encounters.  Certain inline tags, like image tags, links, span tags, etc. will be 
        // adversely affected if they are split out so we'll convert the opening bracket < temporarily to: {@TAG}
        $str = preg_replace("#<(/*)(".$this->inline_elements.")([ >])#i", "{@TAG}\\1\\2\\3", $str);

        // Split the string at every tag.  This expression creates an array with this prototype:
        // 
        //     [array]
        //     {
        //         [0] = <opening tag>
        //         [1] = Content...
        //         [2] = <closing tag>
        //         Etc...
        //     }    
        $chunks = preg_split('/(<(?:[^<>]+(?:"[^"]*"|\'[^\']*\')?)+>)/', $str, -1, PREG_SPLIT_DELIM_CAPTURE|PREG_SPLIT_NO_EMPTY);
        
        // Build our finalized string.  We cycle through the array, skipping tags, and processing the contained text    
        $str = '';
        $process = TRUE;
        $paragraph = FALSE;
        $current_chunk = 0;
        $total_chunks = count($chunks);
        
        foreach ($chunks as $chunk)
        { 
            $current_chunk++;
            
            // Are we dealing with a tag? If so, we'll skip the processing for this cycle.
            // Well also set the "process" flag which allows us to skip <pre> tags and a few other things.
            if (preg_match("#<(/*)(".$this->block_elements.").*?>#", $chunk, $match))
            {
                if (preg_match("#".$this->skip_elements."#", $match[2]))
                {
                    $process =  ($match[1] == '/') ? TRUE : FALSE;
                }
                
                if ($match[1] == '')
                {
                    $this->last_block_element = $match[2];
                }

                $str .= $chunk;
                continue;
            }
            
            if ($process == FALSE)
            {
                $str .= $chunk;
                continue;
            }
            
            //  Force a newline to make sure end tags get processed by _format_newlines()
            if ($current_chunk == $total_chunks)
            {
                $chunk .= "\n";  
            }
            
            //  Convert Newlines into <p> and <br /> tags
            $str .= $this->_format_newlines($chunk);
        }
        
        // No opening block level tag?  Add it if needed.
        if ( ! preg_match("/^\s*<(?:".$this->block_elements.")/i", $str))
        {
            $str = preg_replace("/^(.*?)<(".$this->block_elements.")/i", '<p>$1</p><$2', $str);
        }
        
        // Convert quotes, elipsis, em-dashes, non-breaking spaces, and ampersands
        $str = $this->format_characters($str);
        
        // restore HTML comments
        for ($i = 0, $total = count($html_comments); $i < $total; $i++)
        {
            // remove surrounding paragraph tags, but only if there's an opening paragraph tag
            // otherwise HTML comments at the ends of paragraphs will have the closing tag removed
            // if '<p>{@HC1}' then replace <p>{@HC1}</p> with the comment, else replace only {@HC1} with the comment
            $str = preg_replace('#(?(?=<p>\{@HC'.$i.'\})<p>\{@HC'.$i.'\}(\s*</p>)|\{@HC'.$i.'\})#s', $html_comments[$i], $str);
        }
                
        // Final clean up
        $table = array(
        
                        // If the user submitted their own paragraph tags within the text
                        // we will retain them instead of using our tags.
                        '/(<p[^>*?]>)<p>/'  => '$1', // <?php BBEdit syntax coloring bug fix
                        
                        // Reduce multiple instances of opening/closing paragraph tags to a single one
                        '#(</p>)+#'         => '</p>',
                        '/(<p>\W*<p>)+/'    => '<p>',
                        
                        // Clean up stray paragraph tags that appear before block level elements
                        '#<p></p><('.$this->block_elements.')#'    => '<$1',

                        // Clean up stray non-breaking spaces preceeding block elements
                        '#(&nbsp;\s*)+<('.$this->block_elements.')#'    => '  <$2',

                        // Replace the temporary markers we added earlier
                        '/\{@TAG\}/'        => '<',
                        '/\{@DQ\}/'         => '"',
                        '/\{@SQ\}/'         => "'",
                        '/\{@DD\}/'         => '--',
                        '/\{@NBS\}/'        => '  '

                        );
        
        // Do we need to reduce empty lines?
        if ($reduce_linebreaks === TRUE)
        {
            $table['#<p>\n*</p>#'] = '';
        }
        else
        {
            // If we have empty paragraph tags we add a non-breaking space
            // otherwise most browsers won't treat them as true paragraphs
            $table['#<p></p>#'] = '<p>&nbsp;</p>';
        }
        
        return preg_replace(array_keys($table), $table, $str);

    }
    
    // --------------------------------------------------------------------
    
    /**
     * Format Characters
     *
     * This function mainly converts double and single quotes
     * to curly entities, but it also converts em-dashes,
     * double spaces, and ampersands
     *
     * @access   public
     * @param    string
     * @return   string
     */
    public function format_characters($str)
    {
        static $table;
        
        if ( ! isset($table))
        {
            $table = array(                    
                            // nested smart quotes, opening and closing
                            // note that rules for grammar (English) allow only for two levels deep
                            // and that single quotes are _supposed_ to always be on the outside
                            // but we'll accommodate both
                            // Note that in all cases, whitespace is the primary determining factor
                            // on which direction to curl, with non-word characters like punctuation
                            // being a secondary factor only after whitespace is addressed.
                            '/\'"(\s|$)/'                    => '&#8217;&#8221;$1',
                            '/(^|\s|<p>)\'"/'                => '$1&#8216;&#8220;',
                            '/\'"(\W)/'                        => '&#8217;&#8221;$1',
                            '/(\W)\'"/'                        => '$1&#8216;&#8220;',
                            '/"\'(\s|$)/'                    => '&#8221;&#8217;$1',
                            '/(^|\s|<p>)"\'/'                => '$1&#8220;&#8216;',
                            '/"\'(\W)/'                        => '&#8221;&#8217;$1',
                            '/(\W)"\'/'                        => '$1&#8220;&#8216;',

                            // single quote smart quotes
                            '/\'(\s|$)/'                    => '&#8217;$1',
                            '/(^|\s|<p>)\'/'                => '$1&#8216;',
                            '/\'(\W)/'                        => '&#8217;$1',
                            '/(\W)\'/'                        => '$1&#8216;',

                            // double quote smart quotes
                            '/"(\s|$)/'                        => '&#8221;$1',
                            '/(^|\s|<p>)"/'                    => '$1&#8220;',
                            '/"(\W)/'                        => '&#8221;$1',
                            '/(\W)"/'                        => '$1&#8220;',

                            // apostrophes
                            "/(\w)'(\w)/"                    => '$1&#8217;$2',

                            // Em dash and ellipses dots
                            '/\s?\-\-\s?/'                    => '&#8212;',
                            '/(\w)\.{3}/'                    => '$1&#8230;',

                            // double space after sentences
                            '/(\W)  /'                        => '$1&nbsp; ',

                            // ampersands, if not a character entity
                            '/&(?!#?[a-zA-Z0-9]{2,};)/'        => '&amp;'
                        );
        }

        return preg_replace(array_keys($table), $table, $str);
    }
    
    // --------------------------------------------------------------------

    /**
     * Format Newlines
     *
     * Converts newline characters into either <p> tags or <br />
     *
     * @access   public
     * @param    string
     * @return   string
     */    
    public function _format_newlines($str)
    {
        if ($str == '')
        {
            return $str;
        }
        
        if (strpos($str, "\n") === FALSE  && ! in_array($this->last_block_element, $this->inner_block_required))
        {
            return $str;
        }
        
        // Convert two consecutive newlines to paragraphs
        $str = str_replace("\n\n", "</p>\n\n<p>", $str);
        
        // Convert single spaces to <br /> tags
        $str = preg_replace("/([^\n])(\n)([^\n])/", "\\1<br />\\2\\3", $str);
        
        // Wrap the whole enchilada in enclosing paragraphs
        if ($str != "\n")
        {
            $str =  '<p>'.$str.'</p>';
        }

        // Remove empty paragraphs if they are on the first line, as this
        // is a potential unintended consequence of the previous code
        $str = preg_replace("/<p><\/p>(.*)/", "\\1", $str, 1);
        
        return $str;
    }
    
    // ------------------------------------------------------------------------
    
    /**
     * Protect Characters
     *
     * Protects special characters from being formatted later
     * We don't want quotes converted within tags so we'll temporarily convert them to {@DQ} and {@SQ}
      * and we don't want double dashes converted to emdash entities, so they are marked with {@DD}
      * likewise double spaces are converted to {@NBS} to prevent entity conversion
     *
     * @access    public
     * @param    array
     * @return    string
     */
    public function _protect_characters($match)
    {
        return str_replace(array("'",'"','--','  '), array('{@SQ}', '{@DQ}', '{@DD}', '{@NBS}'), $match[0]);
    }

    // --------------------------------------------------------------------
    
    /**
     * Convert newlines to HTML line breaks except within PRE tags
     *
     * @access   public
     * @param    string
     * @return   string
     */        
    public function nl2br_except_pre($str)
    {
        $ex = explode("pre>",$str);
        $ct = count($ex);
    
        $newstr = "";
        for ($i = 0; $i < $ct; $i++)
        {
            if (($i % 2) == 0)
            {
                $newstr .= nl2br($ex[$i]);
            }
            else
            {
                $newstr .= $ex[$i];
            }
        
            if ($ct - 1 != $i)
                $newstr .= "pre>";
        }
    
        return $newstr;
    }
    
}
// END Typography Class

/* End of file Typography.php */
/* Location: ./base/libraries/php5/Typography.php */